Arch construction for concrete bridges



W. M. THOMAS. ARCH CONSTRUCTION FOR CONCRETE BRIDGES.

,1917. RENEWED APR. 19,1920.

APPLICATION FILED MAR- 27 1,356,025.

or. M Thor/1 2 W. M. THOMAS.

ARCH CONSTRUCTION FOR CONCRETE BRIDGES.

APPLICATION FILED MAR.27, 1917.

RENEWED APR-19, 1920.

Patented Oct. 19, 1920.

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. @ibrvvep'fi 1 @ww w WILLIAM M. THOMAS, OF LOS ANGELES, CALIFORNIA.

' ARCH CONSTRUCTION FOR. CONCRETE BRIDGES.

Specification of Letters Patent.

Patented Oct. 19, 1920.

Application filed March 27, 1917, Serial No. 157,660. Renewed April 19, 1920. Serial No. 375,162.

To all to 710m it may concern:

Be it known that I, WILLIAM M. THoMAs, a citizen of the United. States, residing at Los Angeles, in the county of Los Angeles 5 and State of California, have inventeda new and useful Arch. Construction for Concrete Bridges, of whichthe following is a specification.

This invention relates to means for mounting arches of reinforced concrete bridges in such manner as to distribute and ,equalize' the strains or pressures at the hinges and to provide adequate and effective hinge bearings for'the arch members. The invention is especially applicable in fconnection with the three hinge arch system of'reinforced concrete bridges.

Other objects of the invention will appear hereinafter.

1 The accompanying drawings illustrate an embodiment of my invention, and referring thereto:

F igure 1 is a side elevation of an arch, showing the supporting piers in section, the supporting hinge being shown in incomplete condition at one end of'the arch.

. Fig. 2 is a vertical section on line in -m Fig 1.

1 Fig.

Fig. 4 is a plan view of the parts shown in Fig. 1.

Fig. 5 is a vertical section of the crown portion of the arch members showing the crown hinge.

Fig. 6 is a section on line w-m, Fig. 5.

3 is a vertical section on line ww Fig. 7 is a view similar to Fig. 5 showing a modified form of the crown hinge. Fig. 8 is a section on l1ne w 'm Flg. 7.

formsof the invention.

The arch rib to which my invention is applied is assumed to be composed of two arch beams or members 1, resting at their lower ends on piers 2 and connected at their upper ends by a'crown hinge. The arch beams 1 are rounded at their lower ends to form semicylindrical bearing faces 1. The piers 2 are of any suitable construction, and each pier is provided with-vertical projectionsor arch abutmentsconsisting, for example,- of T-beams 3embedded in the rein- I "forced concrete, orjother material of the pier. f In constructing the piers they are formed temporarily with horizontal bearing inces and the I-beams or a u ment mem- Figs. 9 and 10 are side elevations of other bers 3 project above these bearing faces so that the arch membersl may be caused to rest at their lower ends on said bearing faces and against said abutment members, as shown at the right hand of Fig. 1. When the two arch members have been assembled and connected together at their upper ends by the crown hinge as hereinafter set forth,.

their lower ends will be supported by the bearing faces 5 and by the abutment members 3 so as to hold the arch ribs in proper position. Mold boards or members 7 are then placed around the upper part of each pier, so as to surround the lower portions of the arch ribs and concrete or cement indicated B at 8 isfthen poured or run into these mold 7 tain a movable hinge bearing for the arch beam. By forming the hinge bearing. in

this manner after the arch beamhas been set up, a uniform and effective bearing is secured over the entire bearing face'l of each arch beamyso that the strains and pressures are equalized throughout the hinge surface.

Means are provided at the crown of the arch for equalizing the strains by means of a hinge jointwhich is self adjusting to the positions of the arch beams. For this purpose, the arch beams are provided with an interlocking key member which engages with both of them when they are in position, and bearing members of deformable or malleable material such as lead, are interposed between said key member' and the respective arch beams so as to enable the several parts to accommodate themselves to one another and provide a uniform bearing throughout. Thus, as shown in Fig. 5, the arch beams 1 are provided at their upper ends with sockets 10 for receiving a key member 12 and lead bearing plates 13 are providedbetween said key member 12 and metal bearing plates 14. at the bottom of said sockets. Said bearing plates 14 are riveted or other i s cur d to metal i m er for example, I-beams l5 embedded in the arch beams l. Plates or projections 16 on the bearing plates 14 extend above and below the key member 12-to retain the same in position, these members 16 also serving to confine the lead bearing plates 13 and.

prevent them from spreading under the pressure of the key '12 and bearing plate 14. In placing the arch beams in position, they are lifted by suitable means not shown, and their lower ends are-brought onto the piers, as above described, while their upper ends are raised slightly above their final position, so as to be separated sufficiently to enable the key member 12 to be slipped into the sockets 10. The arch beams are then lowered intoposition, causing them to close upon the key member, whereupon said key member engages the lead plates 13 and any tendency of the key member to hear at any particular point, causes the lead to be squeezed from such part to other parts of thebearing, so that eventually the bearing becomes uniform over the entire'surface of the key member and under such conditions there is no lateral or canting strain on the arch beam, such as would arise from such localized bearing and would be liable to crush the bearing parts owing to the great pressures involved.

The key member 12 is shown in Fig. 5, as of rectangular cross section and is made hollow for the sake of lightness. member may, however, be made circular in cross section, as shown at 20 and Figs. 7 and 8, and in that case is seated in twosemicylindrical socket members 21' in the respective arch rib-member 1, and a lead plate 22 is inserted between said key member and said socket members, the cylindrical walls of the socket members serving in this case to confine the yielding lead plate 22 so as to prevent spreading thereof while permitting the lead plate to adjust itself between the surfaces of the key member and the sockets.

The self adjusting hinge construction above described may be used at the spring orouter hinge of the arch at each end, and

as well asat the keyor crown hinge. Thus, as shownan Fig. 9, the "arch members 24 are provided withsockets 25 in their respectiveends, adapted to receive theself'adj tin'g lead plates 26 within which engage the seinicylindrical hinge or bearingmemhers 27 on the respective piers 28. Iii-place of these hinge bearings being semicvlindrical they may be of any shape, forexainple. segmental as shown in Fig. l0,and the key member may be dispensedwith, each arch member 24- being provided at oneend with a concave socket portion 29 and at the other end with a convex hinge .portionBO corresponding tosaid socket portion, an-inter vening. lead plate 31 being provided between such hinge portions and the end of the arch Said key and correspondingly formed hinge portions 38 and 83 on the'piers. In the construction shown in Fig. 10, either of hinge portions described may be molded conformably to the other cooperating hinge portion as above described in connection with the pier struction, preformed reinforced concrete arch beams having rounded faces at their lower ends and piers provided with means for supporting the lower ends of said beams, metallic reinforcing members in said piers extending vertically therein and engaging the lower ends of said arch beams, and concrete embedding said metallic reinforcing means at said rounded hinge faces of said arch beams.

3. In a reinforced concrete bridge, the combination of preformed concrete arch beams having sockets at their upper ends, a key member engaging said sockets and bearing plates of malleable material between said key member and the arch ribs, said sockets in the arch ribs being formed with shoulders extending above and ,below said key member and confining said lead bearing plates.

l. In a reinforced concrete bridge of the three-hinge arch type, the combination with the arch formed of two arch beams of a self adjusting bearing between the upper ends of said arch ribs forming a crown hing'e thereof a bearing member of malleable material between said 'bearlng'and-nr'ch beam, and means forholding said bearing member in position.

5. The method of making an arched structure, which method consists in partly embedding abutment members in suitable pier-formin g material, forming an a'r'ch' with bearing faces atits ends, placing the arch with its bearing faces resting against the 'abutments, and then casting concrete around the ends *of the arch.

6. Themethod of-making an arched structure, which method consists inpartly embedding-abutment members in suitable .pierforming material, preforming a concrete arch with -metal bearingplates at] its ends, placing the arch with its bearing plates resting against the abutments. and then casting concrete around the ends of the arch.

7. The method of making an arched structure, which method consists in partly'embedding abutment members in suitable pierforming material, forming an arch in sections with bearing faces at both ends of the sections, placing the sections with the bearing faces at one end resting against the abutments respectively and with the bearing faces at the other end spaced slightly apart,

inserting a bearing member of malleable ma- 10 terial between the adjacent bearing faces,

lowering the adjacent ends of the sections to Signed at Morgantown, West Va., this 15 23rd day of March 1917.

WILLIAM M. THOMAS. Witnesses EUGENE J. KERSTING, PAUL H. KEENER. 

